The present invention relates to an apparatus for status monitoring of an actuator in a flying device and a corresponding method therefor.
It is the objective of status monitoring of components in a flying device, in English often also referred to as health monitoring, to at any time obtain information concerning the structural integrity, the remaining service life or further safety-related information on the component. It is of fundamental interest to be able to predict the failure of a component in a flying device, in order to be able to take countermeasures before the occurrence of the damage. It is the objective of health monitoring to obtain the current status of the monitored systems, for example of an actuator, in order to coordinate maintenance tasks for the flying device and to prevent the occurrence of safety-critical faults.
Conventional health monitoring methods in the field of aviation relate to the airframe or to the structural integrity of a landing gear. The methods for monitoring structural components as used here, which are based on fracture mechanics, have been examined in detail in the prior art and presently constitute the standard practice in health monitoring of an airframe and a landing gear. It should be noted that the design of the elements monitored here, such as for example the airframe, is effected in a fault-tolerant way. Upon occurrence of a crack in an airframe, the propagation of this crack first is monitored and subsequently damage-limiting measures are carried out.
From EP 1815224 A1 health monitoring for an aircraft landing gear is known. Like in the prior art discussed above, health monitoring mostly relates to the structural integrity of large components.
For determining the structural integrity of large components, the vibration behavior of the components generally is measured and the measurement data obtained are transformed into the frequency range. By means of a filter, in the optimal case by means of a matched filter or a Kalman filter, a vibration behavior subsequently is searched which is typical for a damaged or structurally weakened component. For this targeted filtering operation it is however necessary to know how the basic shape of the signal to be searched in the frequency range should look like, so that the filter matched thereto can detect the signal shape sought for. This knowledge only is obtained by a multitude of non-destructive and destruction-bound test series of the aircraft components to be examined. The operation experience of similar components and the operation experience of the actual component additionally contribute decisively to these extensive data. Hence it is necessary that the component to be examined is available long enough in advance, so that sufficient time is left to carry out the test series.
As shown, the database for such method is very large, so that the memory capacity required therefor is immense. In addition, the memory capacity required is additionally increased by the necessary real-time recording of a multitude of sensors (for example vibration sensors) not defined further. The expenditure for the communication between the data acquisition at the sensor and a memory unit also is considerable, so that an increased susceptibility to malfunctions and failures beside additional costs of examination, acquisition, operation and maintenance leads to a reduction of the overall safety and/or to a reduction of the system availability.
As mentioned already, it is disadvantageous in the known prior art that prior to health monitoring a particularly large database expensive to generate must be created, as only in this way the signal shape of an error or an error occurring soon can be detected. It therefore would be wrong to transfer the application of the conventionally used system to less relevant components of a flying device. This would lead to a strong increase of the costs of an aircraft development or the development of a component of a flying device and at the same time increase the weight of the flying device, as the necessary components for conventional health monitoring would have to be incorporated in addition.